Three "terrorists" were killed and soldiers are continuing to comb the building floor by floor "looking for anyone left behind", officials said.

The Kenyan Red Cross has told the BBC that 63 people remain unaccounted for.

'Under control'

Analysis

By Jonathan BealeDefence correspondent, BBC News

A number of countries are believed to have offered assistance to the Kenyan authorities currently dealing with the siege at the Westgate Mall.

Kenya is seen as a largely pro-Western country in a strategically important continent that is facing growing instability from the threat of Islamic extremism.

Western interests in Kenya have also been targets in the past - most notably the 1998 attack on the US embassy in Nairobi carried out by al-Qaeda.

However, at present, Kenya's forces are taking the lead in the hostage crisis. If there is any involvement by foreign nations, it's likely to be in a purely advisory role. It has already been reported that Israeli "security specialists" are on the ground in Nairobi giving advice, although this has not officially been confirmed.

Even if foreign forces are giving advice or even more, the Kenyan authorities are unlikely to want to give the impression that they cannot deal with this crisis themselves.

The official death toll stands at 62 and more than 170 have been injured. There are fears the death toll will rise further.

British Defence Secretary Philip Hammond said that his best estimate was that six Britons had been killed.

The Somali Islamist al-Shabab movement has said it carried out the attack in retaliation for Kenyan military operations in Somalia.

"The terrorists could be running and hiding in some stores, but all floors now are under our control," Kenyan Interior Minister Joseph Ole Lenku said.

"There is no room for escape."

He told the BBC late on Monday that the operation would continue overnight, but stressed it was in its final stages.

The minister added that "it is very unlikely that there are any hostages" left in the complex.

Flames

The BBC's Gabriel Gatehouse, who is at the scene, says there is still no clear picture of what is going on inside; officials have said forces are in control of the mall but have not said if they have arrested or killed all attackers.

As night fell on Monday, flames and thick smoke continued to rise from the complex.

The Kenya Defence Forces said the fire had been started by "terrorists to distract the ongoing operation", and that the blaze was being managed by firefighters.

President Barack Obama said the US was offering its full support to the Kenyan authorities.

Kenya is one of the largest recipients of US security assistance in sub-Saharan Africa, with much of that aid focused on counter-terrorism.

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Media captionPresident Obama says the US stands with Kenya

The BBC's defence correspondent Jonathan Beale says the US is likely to have responded to the crisis by sending one of its Foreign Emergency Support Teams (Fest).

But there was no suggestion they are directly involved, our correspondent says.

The KDF said 10 bodies had been retrieved from the building in the last 24 hours. More than 200 civilians have been rescued, 65 of whom remain in hospital.

Eleven KDF soldiers were injured during the operation, it said.

Earlier, police used tear gas to disperse crowds of onlookers gathered close to the Westgate Centre.

The Interior Ministry has been issuing regular warnings for people to stay away for their own safety.

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Thick black smoke started billowing from the building shortly after blasts were heard

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The Kenyan interior minister said security forces were gaining an advantage over the militants

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Kenyan police officers took position around the Westgate Shopping Centre

Image caption
Police fired tear gas to try to disperse crowds of onlookers near the centre.

Security has also been stepped up at entrance and exit points across the country, with "more than 10 individuals" arrested in relation to the attack, the ministry said.

It did not specify when or where the arrests were made, but media reports from Kenya said the suspects were detained at the Jomo Kenyatta International Airport.

Repeated threats

More than 1,000 people were inside the mall complex when the attack began on Saturday.

Dr Sunil Sachdeva, a dentist who runs a clinic inside the mall, described the scene as the attack unfolded.